The most luminous galaxies in the universe are overa
thousand times more powerful than our Milky Way...yet they are not
especially bright at optical wavelengths! They were instead discovered
in the infrared. It seems they are powered by bursts of massive
star formation: clusters of massive stars, each
star thousands or even tens of thousands of times more
luminous than our Sun, and all of them buried in dusty natal clouds of
material that block their visible light. Massive stars, however, are
also very short-lived, lasting perhaps only tens of millions of years
before exploding in as supernovae (compared with our Sun's current age
of 5 billion years). Hence these luminous galaxies are called
starburst galaxies, and they are indeed lit up in short bursts of
star forming activity. Messier 82 in the constellation of Ursa
Major is a nearby example of a luminous starburst galaxy, and the
multi-wavelength image at the left reveals the dramatic disruptive
power of the strong winds produced by all of those massive young stars.

Why? What causes a galaxy
to go wild and suddenly produce massive new stars? Is this a
normal phase that every galaxy must undergo? Did the Milky Way
itself have a starburst...or will it perhaps erupt in the future?
Massive stars produce and disperse most of the chemical elements
essential to life ... did the carbon, oxygen, and iron on Earth
come originally from a starburst? Because starburst galaxies are so
bright (at least in the infrared) they can be seen to almost the edges
of the known Universe -- what can these fantastically remote objects
tell us about stars, galaxies, and the physics at cosmological
distances, when the universe was in its infancy?

These are some of the questions which CfA scientists are trying to answer in their studies of Starburst Galaxies.